Stone and rock removing device

ABSTRACT

A device for removing stones and rocks intermixed with harvested potatoes comprising a conveyor for receiving and conveying same one by one in contiguous relationship with a sensor transmitting mechanical vibrations whereof those vibrations caused by a stone or rock exceed a predetermined level and whereby such discrete vibrations are converted by a crystal pickup to signal voltages and in conjunction with circuit means therefor energize a solenoid operatively connected to a valve to effect communication from a pneumatic source to an air cylinder to reciprocate a plunger ram to eject such stone or rock.

United States latei [72] Inventors Richard Nelson Cragg, deceasedCohocton, N.Y.; Patricia A. Cragg, Administratrix; William E. Cragg,Administrator [21 Appl. No. 742,042

[22] Filed July 2, 1968 [45] Patented Feb. 2, 197] [54] STONE AND ROCKREMOVING DEVICE l9 Claims, 11 Drawing Figs.

52 use: v. 209 73,

209/82 511 lnt.Cl 1mm 5 54 501 FieldoiSearch ..209 s2,73,

[56] References Cited UNITED STATES PATENTS 2,712,753 7/1955 Campbell324/80X 3,435,950 4/1969 Suverkrop 209/1 1 1.9X

Primary Examiner-Allen N. Knowles AtI0mey-Lowe and King ABSTRACT: Adevice for removing stones and rocks intermixed with harvested potatoescomprising a conveyor for receiving and conveying same one by one incontiguous relationship with a sensor transmitting mechanical vibrationswhereof those vibrations caused by a stone or rock exceed apredetennined level and whereby such discrete vibrations are convertedby a crystal pickup to signal voltages and in conjunction with circuitmeans therefor energize a solenoid operatively connected to a valve toefiect communication from a pneumatic source to an air cylinder toreciprocate a plunger ram to eject such stone or rock.

PATENTEU as m 3559.805

SHEET 1 [IF 4 INVENTOR. RI 0 HARD NELSON CRAGG PATENTED FEB 2 I97! SHEET2 [IF 4 INVENTOR.

RICHARD NELSON CRAGG BY PATENTED rm 2m: 3.559.805

' mm 3 0P4 Fl G. 5.

J+ m m In '0 l INVENTOR.

RICHARD NELSON CRAGG PATENIEU FEB- 2191:

SHEET s 0F 4 CTRONIC AMPLIFIER RECTIFIER DETECTOR 5mm RELAY FIGJO.

INVENTOR.

RICHARD NELSON CRAGG BY wamawwy.

STONE AND ROCK REMOVING DEVICE The present invention generally relatesto separating apparatus, and in particular to agricultural separatingapparatus utilizing mechanical sensing means wherein harvested crop andforeign object mixtures are transported past density responsive sensingmeans, and control signals are generated to eject the foreign objectsfrom the mixture.

The problem of the art to which this invention apertains is the need fora stone and rock removing device which will function and operateeconomically to remove stones and rocks intermixed with harvestedpotatoes. The potato, as one of the world s most valued and widely grownvegetables, grows 4 in relatively poor soil with little attention. Uponharvesting potatoes grown in soil containing stones and rocks, thestones and rocks are harvested along with the potatoes. This describedsituation requires the expenditure of time, money and effort in removingthe stones and rocks from the harvested potatoesusually by hand. Theincreasing cost factor of labor necessary to remove the intermixedstones and rocks from the harvested potatoes grown in such soilmilitates against such growing of potatoes. With such increasing costfactor of labor, it becomes increasingly uneconomic to grow and harvestpotatoes in marginal soil having stones and rocks.

According to the present invention, an agricultural separating apparatusfor sorting foreign objects such as stones and rocks from harvestedcrops, such as potatoes, comprises a conveyor for receiving andtransporting the intermixed foreign objects and harvested crops inone-by-one seriatim fashion. The sensing means are positioned beside theconveyor so as to have a contiguous relationship with the intermixedforeign objects and harvested crops. The sensor means is responsive tothe differences in density or momentum between the foreign objects andharvested crops as they are transported along the conveyor; the sensormeans generates pickup signals indicative of these differences. Controlmeans receive the pickup signals generated by the sensor and controlejecting means such as a plunger ram to eject the foreign objects fromthe intennixture.

A feature of this invention is that sorting apparatus transports anintennixture of objects to be sorted past sensing means in one-by-oneseriatim and contiguous fashion. The sensing means is responsive to thephysical property of density or to the momentum of the intermixedobjects, and generates signals in response thereto. Certain of theintermixed objects, i.e., rocks and stones, will have a large enoughdensity such that the signal generated by the sensor will activatecontrol means to cause ejection of those objects from the mixture.

It is, accordingly, an object of the present invention to provide a newand improved agricultural separating apparatus for removing foreignobjects from harvested crops.

Another object of the present invention is to provide an agriculturalseparating apparatus for automatically removing foreign objects such asstones and rocks from harvested crops.

Another object of the invention is to provide a new and improvedagricultural separating apparatus for sorting foreign objects andharvested crops, and operating on the physical property of densities ofthe intermixed objects.

Another object of the invention is to provide a new and improvedagricultural separating device wherein every object to be sorted by thedevice contacts a sensor.

This object and other objects of the invention should be discerned andappreciated from the detailed specification taken in conjunction withthe drawings, wherein like reference numerals refer'to similar partsthroughout the several views, in which:

FIG. 1 is an elevation view of the device showing potatoes beingcollected in a collecting bin;

FIG. 2 is an end view of the device in the direction of the arrow2"ofFlG. 1;

FIG. 3 is a perspective view of the device;

FIG. 4 is a perspective view of the sensor and the box housing thecrystal pickup;

FIG. 5 is a representation of the topology of the circuit utilized inthe invention;

FIG. 6 is a block diagram representing the subfunctions of theelectrical circuit;

FIG. 7 is a representation of the AC signal voltage generated by thecrystal pickup;

FIG. 8 is a representation of the signal voltage of FIG. 7 as amplifiedby the amplifier stage;

FIG. 9 is a representation of the amplified signal voltage of FIG. 8 asrectified by the rectifier stage;

FIG. 10 is a representation of the rectified signal voltage of FIG. 9 assensed by the detector in excess of the detect level causing theelectronic switch to operate;

FIG. 11 is a representation of the relay or solenoid energized by theelectronic switch characterized in FIG. 10.

Reference is now made to FIGS. 1, 2 and 3 wherein numeral I generallyrefers to the invention of the stone and rock removing device. Harvestedpotatoes containing intermixed stones and rocks 3 are shown carried on aconveyor belt 5 of a conventional potato harvester. These harvestedpotatoes 3 are deposited upon the conveyor belt 7 of the invention.

The conveyor incorporated in the device is of the gravitydischarge type.Its continuous conveyor belt 7 is trained around idler pulley 9 anddriven pulley 1 1. Driven pulley I1 is fixed to common shaft 13 to whichdriven pulley 15 is corotatably mounted. Drive is imparted to drivenpulley 15 by means of drive motor 17 having a drive pulley 19 fixedlymounted on its drive shaft with a V-pulley belt 21 trained over thedriven pulley 15 and drive pulley 19.

Frame 23 slidably mounts a plate 25 on each side of the idler pulley 9.Each plate 25 journals the end of the shaft carrying the idler pulley 9.Each plate 25 is adjustably movable in a horizontal direction, as viewedin FIG. 1, by tightening or loosening of nut 27 on screw rod 29 fixed toplate 25. Plates 25 with their associated nuts 27 and screw rods 29function with respect to frame 23 as a pulley tightener for conveyorbelt 7 by appropriate tightening of nuts 27.

Common shaft 13 is mounted in bearing 31 upstanding from frame 23 andjoumaled in journals 33 and 35 upstanding from frame 23.

As viewed in FIG. 1, the legs depending from the left side of frame 23are relatively higher than the legs depending from the right side offrame 23 such that the conveyor of the device with its associatedconveyor belt 7 will function and operate as a gravity-discharge type ofconveyor in order that potatoes deposited and conveyed on the conveyorbelt 7 from the left side to the right side will fall by gravity intothe collecting bin 37.

As viewed in FIG. 2, the leg 39 depending from the right side of frame23 is higher than leg 41 depending from the left side of frame 23 inorder that the potatoes, stones and rocks being conveyed on conveyorbelt 7 will be constrained by gravity to be carried therealong inabutting and guiding relationship by back wall 43 upstanding from guideplate 45 carried on frame 23.

As shown, guide plate 45 is substantially of L-shaped configuration withits bottom plate 47 disposed horizontally and backwall 43 disposedvertically. Backwall 43 has a section 49 articulated angularly. withrespect to backwall 43. The terminal end portion 51 of this articulatedsection 49 is arranged and constructed to be disposed in proximalrelationship with the sensor 53 of crystal pickup 55 (FIG. 4) housed inbox 57 containing insulation 59 for vibration dampening.

Bottom plate 47 mounts box 57, as shown. Carried beneath bottom plate47, as shown, is box 61 which houses the electrical components of theinvention. Carried on bottom plate 47, as shown, is a common commercialpneumatic valve 63. Mounted on bottom plate 47 by U bolts 65, as shown,is the air cylinder 67.

Pneumatic valve 63 is of the common commercial type such as the Versavalve, Model No. FSG-4322, manufactured by Versa Products Co., Inc.,Coolidge Avenue, Englewood, New Jersey. Valve 63 comprises a solenoid orrelay 69 whose armature is compression-spring biased foi' return upondeenergization, a valve body 71 whose two-way piston is operativelyconnected for reciprocation to the solenoid armature, an intake port 73in communication with a pneumatic source (not shown) by air hoseconnection 75, and two outlet ports 77 and 79 communicating byrespective air hoses 81 and 83 to respective inlet ports 85 and 87 ofair cylinder 67. Air cylinder 67 has a plunger ram 89 operativelyconnected to a two-way piston housed within air cylinder 67.

When solenoid 69 is energized, communication with the pneumatic sourceis established to intake port 73, through the left side of the two-waypiston in valve body 71 as viewed in FIG. 3, to outlet port 77, throughair hose 8], to inlet port 87, thereby reciprocating the two-way pistonof the air cylinder 67 outwardly with plunger ram 89 ejecting fromconveyor belt 7 any stone or rock which at the instant of activation ofram 89 is in front of ram 89. The outward position of plunger ram 89 isshown by dashed lines in FIGS. 2 and 3. When solenoid 69 is deenergized,its operatively associated compression spring constrains the two-waypiston of the valve body to its return reciprocating movement thuslyestablishing communication with the pneumatic source through the rightside of the twoway piston in valve body 71 as viewed in FIG. 3, tooutlet port 79, through air hose 83, to inlet port 89, therebyreciprocating the two-way piston of the air cylinder 67 inwardly withplunger ram 89 disposed in its retracted position shown by the solidlines in FIGS. 2 and 3. While solenoid 69 is deenergized, plunger ram 89is maintained in its retracted position by the communication establishedwith the pneumatic source, as described. It should further beappreciated that, whether in the operative or retracted position ofplunger ram 89, the pressurized air from the pneumatic source iscontinuously being bled to atmosphere to facilitate the reciprocation ofthe air-cylinder piston in its operative and retracted movements.

It should further be appreciated that the described gravitydischargetype of conveyor of the invention, along with the described tiltedconveyor belt 7, arranged and constructed with the backwall 43 and itsangularly articulated section 49, cooperatively functions to conveypotatoes, stones and rocks one at a time in contiguous, touchingrelationship with sensor 53 thereby imparting mechanical vibrationsignals to sensor 53.

inasmuch as the stones and rocks have a greater density and hardnessthan potatoes, a different mechanical vibration is imparted to thesensor 53 when same is struck or touched by stones and rocks as comparedto potatoes. These mechanical vibration signals are in turn transmittedto the crystal pickup for conversion into voltage signals by thetransducer function of the pickup. The crystal pickup 55 is covered witha plastic material to insulate it against other than the discretemechanical vibrations transmitted by the sensor 53. The insulation 59 inbox 57 additionally provides protection against jarring or externalvibrations that might be transmitted to the crystal pickup 55 andlikewise serves to attenuate such externally transmitted vibrations suchas through frame 23.

The function of the electrical circuit is to energize solenoid or relay69 whenever discrete mechanical vibrations imparted to sensor 53 andtransmitted to crystal pickup 55 in turn generate AC signal voltageswhich exceed a predetermined level.

The subfunctions of the electrical circuit are represented in FIG. 6.The AC signal voltage generated by crystal pickup 55 is represented byFIG. 7. The subfunction of the amplifier of increasing or amplifying theAC signal voltage generated by the crystal pickup to a higher amplitudeis represented by FIG. 8. The subfunction of the rectifier is to causethe AC portion of the voltage to be all on the same side with referenceto the initial DC level and is represented in FIG. 9. The subfunction ofthe detector is to sense only that portion of the signal voltage thatexceeds the detect level and will cause the electronic switch tooperate, and is represented in FIG. 10. The subfunc tion of theelectronic switch, in turn, is to cause the solenoid or relay 69 toenergize and is represented in FIG. ll.

The topology of the circuit used in this invention is shown in FIG. 5.Crystal pickup 55 generates the AC signal voltage which is coupled bythe capacitor 91 to the first amplifier stage comprising resistor 93,resistor 95, transistor 97, resistor 99, resistor 10], transistor 103and resistor 105. The first amplifier stage, in addition to amplifyingthe voltage, also provides an impedance match for the reason that thisconfiguration has a high input impedance and a low output impedance.Capacitor I07 couples the AC portion of the voltage from the first tothe second amplifier stage. The second amplifier stage comprisesresistor 109, resistor 111, resistor 113, transistor 115, resistor 117,transistor 119, resistor l2], transistor 123 and resistor 125. Twostages of amplification are required to achieve the level ofamplification that isnecessary. Capacitor 127, connected across the 12volt power source 129 between the first and second amplifier stages, asshown, functions to prevent feedback by filtering the power supplyvoltage. Capacitor 131 couples the AC portion of the voltage from theamplifier to the rectifier comprising transistor 133 and resistor 135.Transistor 133 is connected in a manner that operates exactly the sameas a diode by allowing current to pass in only one direction and therebyallowing only a negative voltage that is proportional to the signalvoltage to appear at the junction of transistor 133 and resistor 135. Adiode can be used in place of transistor 133 if desired. The detectcircuit comprises resistor 137 and potentiometer 139, in conjunctionwith resistor 141 and transistor 143. Potentiometer 139 is a variableresistor that can control the detect level for optimum operation. Theelectronic switch comprises transistor 143, resistor 145 and transistor1'47. Transistor 143 is normally in saturation. A negative going voltageat the base of transistor 143 will cause it to cutoff. When transistor143 cuts off, the collector goes positive and causes the transistor togo from a cutofi condition to a saturated condition, which, in turn,causes relay or solenoid 69 to become energized. Capacitor 149 isused tostore energy in order to prevent relay 69 from chattering.

Potentiometer 139 permits circuit tuning to allow mechanical vibrationsfrom stones or rocks of a predetermined level, converted into electricalsignals, to pass through the circuit to energize solenoid 69. The devicemay be utilized to separate stones and rocks intermixed with harvestedbeets, onions, etc.

From the description of the construction, function and operation of thevarious components of the invention, it should be appreciated that thespeed at which conveyor belt 7 is driven, and the proximal relationshipof the terminal end portion 51 of section 49, sensor 53 and ram 89, andthe timed sequence of ejection and retraction of ram 89 controlled bythe electrical circuit, are necessarily of a mutually dependentrelationship that, as individual potatoes, stones or rocks are beingconveyed one by one along and up section 49, the sequential action ofejection and retraction of ram 89 will be practically instantaneous toeject a stone or rock and then retract so as not to interfere with animmediately following potato; moreover, the necessity of instantaneousrecycling of the ram 89 should be obvious in the situation of anotherimmediately following stone or rock.

There has been disclosed a new and improved agricultural separatingapparatus useful for separating foreign objects such as stones and rocksfrom harvested crops such as potatoes, beets and onions, for example.The invention operates on the principle of transporting an interrnixtureof the foreign objects and harvested crops in a one-by-one seriatimfashion past a contiguous physical property sensor responsive to thedensity of the intermixed objects. The sensor operates to generateactivating signals indicative of the higher density objects such asrocks and stones while permitting the harvested crops to pass throughwithout generating such an activating signal. The activating signal isutilized to energize an ejecting mechanism to separate those foreignobjects from the intermixture.

While there has been described and illustrated one specific embodimentof the invention, it will be clear that variations of the details ofconstruction which are specifically illustrated and described may bemade without department from the true spirit and scope of the inventionas defined in the appended claims.

lclaim:

l, A device for removing stones and rocks intermixed with harvestedpotatoes; said device comprising a conveyor, sensor means, control meansand a plunger ram; said conveyor receiving and conveying the intermixedstones, rocks and potatoes by said sensor in a one-by-one contiguousrelationship with said sensor means, said sensor means, generatingpickup signals proportional to the density of each stone, rock andpotato touching said sensor means and transmitting said pickup signalsto said control means, said control means controlling the operation ofsaid plunger ram, and said plunger ram ejecting said stones and rocks.

2. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim I, wherein said conveyor furthercomprises a backwall and an angularly articulated section, wherein saidbackwall and articulated sectiori are vertically disposed relative tosaid conveyor, wherein said section is articulated angularly relative tosaid backwall, and wherein said backwall and articulated sectioncooperate to convey the potatoes, stones and rocks one by one by saidsensor means.

3. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim 1, wherein said conveyor furthercomprises depending legs, a backwall and an angularly articulatedsection, wherein said depending legs are of such relative height toslope said conveyor downwardly toward its discharge end, wherein saidbackwall and articulated section are vertically disposed relative tosaid conveyor, wherein said section is articulated angularly relative tosaid backwall, wherein said depending legs further are of such relativeheight to tilt said conveyor relative to said backwall, therebycooperating to convey the potatoes, stones and rocks one by one by saidsensor means.

4. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim 1, wherein said conveyor furthercomprises a backwall and an angularly articulated section, wherein saidbackwall and articulated section are vertically disposed relative tosaid conveyor, wherein said section is articulated angularly relative tosaid backwall, wherein said articulated section has a terminal endportion, and wherein said terminal end portion, sensor means and plungerram are in such proximal relationship that said plunger ram effectsinstantaneous ejection of a stone or rock touching or striking saidsensor means.

5. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim 1, wherein said conveyor furthercomprises depending legs, a backwall and an angularly articulatedsection, wherein said depending legs are of such relative height toslope said conveyor downwardly toward its discharge end, wherein saidbackwall and articulated section are vertically disposed relative tosaid conveyor, wherein said section is articulated angularly relative tosaid backwall, wherein said depending legs further are of such relativeheight to tilt said conveyor relative to said backwall, therebycooperating to convey the potatoes, stones and rocks one by one by saidsensor means; wherein said articulated section has a terminal endportion, and wherein said terminal end portion, sensor means and plungerram are in such proximal relationship that said plunger ram effectsinstantaneous ejection of a stone or rock touching or striking saidsensor means.

6. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim 1, wherein said control means furthercomprises circuit means, a solenoid, pneumatic source and air cylinder,wherein said circuit means converts discrete transmitted vibrations intoelectrical signals to energize said solenoid, whereimsaid solenoidoperatively establishes communication from said pneumatic source to saidair cylinder, wherein said air cylinder has a piston, and wherein saidair cylinder piston is operatively connected to said plunger ram.

7. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim I, wherein said control means furthercomprises circuit means, a solenoid, pneumatic valve, pneumatic sourceand air cylinder, wherein said circuit means converts discretetransmitted vibrations into electrical signals to energize saidsolenoid, wherein said solenoid is operatively connected to saidpneumatic valve to actuate same, wherein said pneumatic valve hascommunication from said pneumatic source to said air cylinder, whereinsaid air cylinder has a piston, and wherein said piston is operativelyconnected to said plunger ram.

8. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim 1, wherein said conveyor furthercomprises a backwall and an angularly articulated section, wherein saidbackwall and articulated section are vertically disposed relative tosaid conveyor, wherein said section is articulated angularly relative tosaid backwall, and wherein said backwall and articulated sectioncooperate to convey the potatoes, stones and rocks one by one by saidsensor means; wherein said control means further comprises circuitmeans, a solenoid, pneumatic source and air cylinder, wherein saidcircuit means converts discrete transmitted vibrations into electricalsignals to energize said solenoid, wherein said solenoid operativelyestablishes communication from said pneumatic source to said aircylinder, wherein said air cylinder has a piston, and wherein said aircylinder piston is operatively connected to said plunger ram.

9. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim I, wherein said' conveyor furthercomprises depending legs, a backwall and an angularly articulatedsection, wherein said depending legs are of such relative height toslope said conveyor downwardly toward its discharge end, wherein saidbackwall and articulated section are vertically disposed relative tosaid conveyor, wherein said depending legs further are of such relativeheight to tilt said conveyor relative to said backwall, therebycooperating to convey the potatoes, stones and rocks one by one by saidsensor means; wherein said control means further comprises circuitmeans, a solenoid, pneumatic valve, pneumatic source and air cylinder,wherein said circuit means converts discrete transmitted vibrations intoelectrical signals to energize said solenoid, wherein said solenoid isoperatively connected to said pneumatic valve to actuate same, whereinsaid pneumatic valve has communication from said pneumatic source tosaid air cylinder, wherein said air cylinder has a piston, and whereinsaid piston is operatively connected to said plunger ram.

10. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim 1, wherein said conveyor furthercomprises depending legs, a backwall and an angularly articulatedsection, wherein said depending legs are of such relative height toslope said conveyor downwardly toward its discharge end, wherein saidbackwall and articulated section are vertically disposed relative tosaid conveyor, wherein said section is articulated angularly relative tosaid backwall, wherein said depending legs further are of such relativeheight to tilt said conveyor relative to said backwall, therebycooperating to convey the potatoes, stones and rocks one by one by saidsensor means; wherein said articulated section has a terminal endportion, and wherein said terminal end portion, sensor and plunger ramare in such proximal relationship that said plunger ram effectsinstantaneous ejection of a stone or rock touching'or striking saidsensor means; wherein said control means further comprises circuitmeans, a solenoid, pneumatic valve, pneumatic source and air cylinder,wherein said circuit means converts discrete transmitted vibrations intoelectrical signals to energize said solenoid, wherein said solenoid isoperatively connected to said pneumatic valve to actuate same, whereinsaid pneumatic valve has communication from said pneumatic source tosaid air cylinder, wherein said air cylinder has a piston, and whereinsaid piston is operatively connected to said plunger ram.

11. A harvesting device for density sorting an intennixture of foreignobjects and harvested crops comprising sensing means for generatingcontrol signals indicative of the density of each said foreign objectand crop in said intermixture, means for transporting said foreignobjects and crops in a oneby-one sen'atim and contiguous .fashion pastsaid sensing means, and means actuated by said control signals andcapable of distinguishing between control signals indicative of saidforeign objects and said crops for ejecting said foreign objects fromsaid intermixture.

[2. The process of density sorting harvested crops from an intermixtureof foreign objects and harvested crops comprising the steps oftransporting said intermixture in a one-by-one seriatim fashion past asensor. contacting said sensor with each foreign object and harvestedcrop in said intermixture, generating a control signal proportional tothe density of each foreign object and crop in said intennixture, andactuating a sorting mechanism with said control signals generated whensaid objects contact said sensor whereby said foreign objects are sortedfrom said intcrmixture.

13. The harvesting device of claim 11 wherein said sensing meanscomprises a crystal pickup device having a sensor arm which is contactedby each foreign object and harvested crop in said intermixture.

14. The harvesting device of claim 13 wherein said sensing means furthercomprises a plurality of crystal pickup devices having sensor arms. andsaid intermixture is transported in a plurality of one-by-one seriatimcontiguous relationships past said sensing means.

15. The device of claim 1 wherein said sensor means comprises a crystalpickup device having a sensor arm which is contacted by each stone, rockand potato in said intcrmixture.

16. The device of claim 1 wherein said sensing means further comprises aplurality of crystal pickup devices having sensor arms, and saidintermixturc is transported in a plurality of onc-by-one seriatimcontiguous relationships past said sensing means.

17. The device according to claim 1 wherein said control means comprisean amplitude discriminator.

18. The harvesting device of claim 11 wherein said means for ejectingsaid foreign objects from said intermixture comprises an amplitudediscriminator.

19. The harvesting device of claim 11 wherein said means for ejectingsaid foreign objects from said intermixture further comprises a plungerram.

1. A device for removing stones and rocks intermixed with harvestedpotatoes; said device comprising a conveyor, sensor means, control meansand a plunger ram; said conveyor receiving and conveying the intermixedstones, rocks and potatoes by said sensor in a one-by-one contiguousrelationship with said sensor means, said sensor means, generatingpickup signals proportional to the density of each stone, rock andpotato touching said sensor means and transmitting said pickup signalsto said control means, said control means controlling the operation ofsaid plunger ram, and said plunger ram ejecting said stones and rocks.2. A device for removing stones and rocks intermixed with harvestedpotatoes in accordance with claim 1, wherein said conveyor furthercomprises a backwall and an angularly articulated section, wherein saidbackwall and articulated section are vertically disposed relative tosaid conveyor, wherein said section is articulated angularly relative tosaid backwall, and wherein said backwall and articulated sectioncooperate to convey the potatoes, stones and rocks one by one by saidsensor means.
 3. A device for removing stones and rocks intermixed withharvested potatoes in accordance with claim 1, wherein said conveyorfurther comprises depending legs, a backwall and an angularlyarticulated section, wherein said depending legs are of such relativeheight to slope said conveyor downwardly toward its discharge end,wherein said backwall and articulated section are vertically disposedrelative to said conveyor, wherein said section is articulated angularlyrelative to said backwall, wherein said depending legs further are ofsuch relative height to tilt said conveyor relative to said backwall,thereby cooperating to convey the potatoes, stones and rocks one by oneby said sensor meanS.
 4. A device for removing stones and rocksintermixed with harvested potatoes in accordance with claim 1, whereinsaid conveyor further comprises a backwall and an angularly articulatedsection, wherein said backwall and articulated section are verticallydisposed relative to said conveyor, wherein said section is articulatedangularly relative to said backwall, wherein said articulated sectionhas a terminal end portion, and wherein said terminal end portion,sensor means and plunger ram are in such proximal relationship that saidplunger ram effects instantaneous ejection of a stone or rock touchingor striking said sensor means.
 5. A device for removing stones and rocksintermixed with harvested potatoes in accordance with claim 1, whereinsaid conveyor further comprises depending legs, a backwall and anangularly articulated section, wherein said depending legs are of suchrelative height to slope said conveyor downwardly toward its dischargeend, wherein said backwall and articulated section are verticallydisposed relative to said conveyor, wherein said section is articulatedangularly relative to said backwall, wherein said depending legs furtherare of such relative height to tilt said conveyor relative to saidbackwall, thereby cooperating to convey the potatoes, stones and rocksone by one by said sensor means; wherein said articulated section has aterminal end portion, and wherein said terminal end portion, sensormeans and plunger ram are in such proximal relationship that saidplunger ram effects instantaneous ejection of a stone or rock touchingor striking said sensor means.
 6. A device for removing stones and rocksintermixed with harvested potatoes in accordance with claim 1, whereinsaid control means further comprises circuit means, a solenoid,pneumatic source and air cylinder, wherein said circuit means convertsdiscrete transmitted vibrations into electrical signals to energize saidsolenoid, wherein said solenoid operatively establishes communicationfrom said pneumatic source to said air cylinder, wherein said aircylinder has a piston, and wherein said air cylinder piston isoperatively connected to said plunger ram.
 7. A device for removingstones and rocks intermixed with harvested potatoes in accordance withclaim 1, wherein said control means further comprises circuit means, asolenoid, pneumatic valve, pneumatic source and air cylinder, whereinsaid circuit means converts discrete transmitted vibrations intoelectrical signals to energize said solenoid, wherein said solenoid isoperatively connected to said pneumatic valve to actuate same, whereinsaid pneumatic valve has communication from said pneumatic source tosaid air cylinder, wherein said air cylinder has a piston, and whereinsaid piston is operatively connected to said plunger ram.
 8. A devicefor removing stones and rocks intermixed with harvested potatoes inaccordance with claim 1, wherein said conveyor further comprises abackwall and an angularly articulated section, wherein said backwall andarticulated section are vertically disposed relative to said conveyor,wherein said section is articulated angularly relative to said backwall,and wherein said backwall and articulated section cooperate to conveythe potatoes, stones and rocks one by one by said sensor means; whereinsaid control means further comprises circuit means, a solenoid,pneumatic source and air cylinder, wherein said circuit means convertsdiscrete transmitted vibrations into electrical signals to energize saidsolenoid, wherein said solenoid operatively establishes communicationfrom said pneumatic source to said air cylinder, wherein said aircylinder has a piston, and wherein said air cylinder piston isoperatively connected to said plunger ram.
 9. A device for removingstones and rocks intermixed with harvested potatoes in accordance withclaim 1, wherein said conveyor further comprises depending legs, abackwall and an angularly articulated section, wherein said dependinglegs are of such Relative height to slope said conveyor downwardlytoward its discharge end, wherein said backwall and articulated sectionare vertically disposed relative to said conveyor, wherein saiddepending legs further are of such relative height to tilt said conveyorrelative to said backwall, thereby cooperating to convey the potatoes,stones and rocks one by one by said sensor means; wherein said controlmeans further comprises circuit means, a solenoid, pneumatic valve,pneumatic source and air cylinder, wherein said circuit means convertsdiscrete transmitted vibrations into electrical signals to energize saidsolenoid, wherein said solenoid is operatively connected to saidpneumatic valve to actuate same, wherein said pneumatic valve hascommunication from said pneumatic source to said air cylinder, whereinsaid air cylinder has a piston, and wherein said piston is operativelyconnected to said plunger ram.
 10. A device for removing stones androcks intermixed with harvested potatoes in accordance with claim 1,wherein said conveyor further comprises depending legs, a backwall andan angularly articulated section, wherein said depending legs are ofsuch relative height to slope said conveyor downwardly toward itsdischarge end, wherein said backwall and articulated section arevertically disposed relative to said conveyor, wherein said section isarticulated angularly relative to said backwall, wherein said dependinglegs further are of such relative height to tilt said conveyor relativeto said backwall, thereby cooperating to convey the potatoes, stones androcks one by one by said sensor means; wherein said articulated sectionhas a terminal end portion, and wherein said terminal end portion,sensor and plunger ram are in such proximal relationship that saidplunger ram effects instantaneous ejection of a stone or rock touchingor striking said sensor means; wherein said control means furthercomprises circuit means, a solenoid, pneumatic valve, pneumatic sourceand air cylinder, wherein said circuit means converts discretetransmitted vibrations into electrical signals to energize saidsolenoid, wherein said solenoid is operatively connected to saidpneumatic valve to actuate same, wherein said pneumatic valve hascommunication from said pneumatic source to said air cylinder, whereinsaid air cylinder has a piston, and wherein said piston is operativelyconnected to said plunger ram.
 11. A harvesting device for densitysorting an intermixture of foreign objects and harvested cropscomprising sensing means for generating control signals indicative ofthe density of each said foreign object and crop in said intermixture,means for transporting said foreign objects and crops in a one-by-oneseriatim and contiguous fashion past said sensing means, and meansactuated by said control signals and capable of distinguishing betweencontrol signals indicative of said foreign objects and said crops forejecting said foreign objects from said intermixture.
 12. The process ofdensity sorting harvested crops from an intermixture of foreign objectsand harvested crops comprising the steps of transporting saidintermixture in a one-by-one seriatim fashion past a sensor, contactingsaid sensor with each foreign object and harvested crop in saidintermixture, generating a control signal proportional to the density ofeach foreign object and crop in said intermixture, and actuating asorting mechanism with said control signals generated when said objectscontact said sensor whereby said foreign objects are sorted from saidintermixture.
 13. The harvesting device of claim 11 wherein said sensingmeans comprises a crystal pickup device having a sensor arm which iscontacted by each foreign object and harvested crop in saidintermixture.
 14. The harvesting device of claim 13 wherein said sensingmeans further comprises a plurality of crystal pickup devices havingsensor arms, and said intermixture is transported in a plurality ofone-by-one seriatim contiguous relationships past said sensIng means.15. The device of claim 1 wherein said sensor means comprises a crystalpickup device having a sensor arm which is contacted by each stone, rockand potato in said intermixture.
 16. The device of claim 1 wherein saidsensing means further comprises a plurality of crystal pickup deviceshaving sensor arms, and said intermixture is transported in a pluralityof one-by-one seriatim contiguous relationships past said sensing means.17. The device according to claim 1 wherein said control means comprisean amplitude discriminator.
 18. The harvesting device of claim 11wherein said means for ejecting said foreign objects from saidintermixture comprises an amplitude discriminator.
 19. The harvestingdevice of claim 11 wherein said means for ejecting said foreign objectsfrom said intermixture further comprises a plunger ram.